Search GardenSeeker

Pruning Magnolias

Most Magnolia varieties grow to a regular shape with an open
centre. They rarely need to be pruned for ‘shade’ purposes. If
planted in the right place, then Magnolias rarely if ever need
any pruning.

Understanding the growth habit of your proposed Magnolia, will ensure
that you plant it in a sittuation where it does not need any pruning
whatever, and will reward you with years of blooms – almost regardless
of the weather. Almost – for Magnolias sometimes fall foul of late or
hard frosts. Such damage can rob
you of flowers for a whole year, and no pruning of any kind will help –
other than to remove unsightly the dead blooms!

Some Magnolias grow into a wide bowl or chalice shape – Magnolia x
soulangeana, others grow into a
large conical shrubs – Magnolia soulangeana
Heaven Scent, whilst some form a
mass of branches and twigs – but remain reasonably small and slower
growing – Magnolia stellata. A few are evergreen – requiring different
treatments if they are to be grown as wall shrubs!

When to Prune Magnolias

Magnolias – x soulangeana types in particular are relatively quick
growing once established. Therein is a little problem in any hard
pruning of these types. They tend to send out many shoots from the
pruned cut – leaving you with the choice then, of which ones to prune
and which to keep.

All Magnolias are tip flowering, on growth – branches or twigs – that
were formed in the early part of the previous year. They require time to
develop the flowering bud, and often these are not visible until late in
the winter. Leaf buds are somewhat similar, and are often mistaken as
being flower buds.

If any pruning is to be done,
then it will need to be carried out in the dormant period – early to
late winter. This invariably means that you will be cutting off the
flower buds with the pruned branch, but to leave pruning until spring or
summer, will mean sap bleeding, and subsequent die back of the pruned
shoot or branch.

Pruning carried out in the dormant season should mean that growth
will start early in spring following, and the development with some
flower buds as well. Many Magnolias flower on the tips of lateral
branches, so for a profusion of flower, little or no pruning will ensure
a gradual build up if these lateral growths.

How
to Prune Magnolias

Sometimes Magnolias get damaged with heavy snow fall or in high winds
when in full leaf. Whilst most are open crowned, which allows the wind
through, they are also quite brittle in the early spring - sometimes
leading to unexpected damage.

In the case of damaged branches that need to be pruned during the
spring or summer, do the least possible as a first aid measure, and cut
only to the first healthy shoot back from the damage or break. There
will almost certainly be some dieback – as well as vigorous water shoots
, but disease is rarely a problem. Pruning proper, can take place later
in the year - winter.

Any hard pruning will almost certainly result in the straggly or
whipcord shoots known as water shoots. Most
of these will need to be cut out, and the cycle begins!

With
any pruning – for space, or misguided aesthetic reason, only prune the
thinnest shoots, and then back by just one third at most.If the cut is taken back to a strong lateral shoot, then there is
less chance of the watershoots developing.

Shaping Young Magnolias

Young Magnolias straight from the garden centre or nursery, have
rarely had any ‘formative’ pruning carried out. The reason being that
Magnolias are normally sold by size- or even by the number of flower buds present! Formative pruning
either reduces the size and bulk of the ‘investment’ and normally takes
off the valuable flower buds! (To test this out, simply have a look at
the Magnolias on sale from late winter, and you will see the ‘added’
value that is placed on flowerbuds.

When first bought, if the Magnolia looks a good shape, then leave
well alone. If it is a ‘stellata’ type, then don’t tamper full stop! It
is meant to be a mass of twigs. But prune out any water shoots that may
have been allowed to develop in the Nursery – accidentally of course!

The white magnolia clearly shows the framework of
flowering lateral branches developed over the years by minimal pruning.

Pruning
Evergreen Magnolias

Magnolia grandiflora
is the main evergreen Magnolia which - if allowed - will grow into a
very large, broad, but slightly conical shrub - or small tree.

This summer flowering Magnolia - with huge cream white goblets of
flowers -It is often grown against a house wall. A spectacular covering
if you have the space! If grown as a large stand-alone shrub, then prune
as for any other
evergreen shrub. If trained against a wall, then prune shoots
directly after flowering - back to a spur of around 12 long - that is to
say back to around the third bud from the main framework.